"An obese child is five times more likely than a non-obese child to be obese as an adult," he said.
The 2015-16 New Zealand Health Survey showed about one in three adults were obese, and one in three adults were overweight.
"The regional results from the 2011-14 New Zealand Health Survey show that the proportion of children that are obese or overweight in the Bay of Plenty and Lakes areas is similar to that across New Zealand," Miller said.
Growing Up in New Zealand recruited 6822 pregnant women who were due to have their babies between April 25, 2009, and March 25, 2010.
Interviews were completed with 6156 children in the Growing Up in New Zealand cohort.
Miller said the increased prevalence of overweight and obesity in children was one of the most significant long-term health challenges.
"The issue is that as a society we have created an environment where all children, even by the young age of 4, have been put at increased risk of being overweight or obese."
He said sugary drink-free policies and healthy food initiatives led by schools, early childhood education centres, councils and workplaces could help turn the "obesity epidemic" around.
"Increased consumption of processed and packaged foods that are high in sugar, fat and salt has contributed to conditions such as obesity, high blood pressure and type 2 diabetes being seen more often in children."
Food product reformulation that progressively reduces hidden sugar content, policies that increase local availability and affordability of fresh and whole foods would also help children enjoy healthy lives free of obesity risk, he said.
Miller said there could be council-planned approaches to reduce children's exposure to unhealthy food environments such as fast food outlets and dairies, and regulation of the marketing of unhealthy food and drink products - as well as a focus on investment in healthy pregnancies.
He said enjoying five or more vegetables and fruits a day, limiting screen time to less than two hours a day, play actively for more than one hour each day, and excluding sugary drink could contribute to a healthy lifestyle.
Children aged 4 have the opportunity to have a B4 School Health Check.
"The age of 4 years is a good time to identify and address any health, behavioural, social, or developmental concerns which could affect a child's ability to get the most benefit from school," Miller said.
Helping families get healthy
Sport Bay of Plenty helps support families to live healthier through its Play in the Bay and Active Families programmes.
Play in the Bay is an online directory to see what it is available in the community.
Sport BOP community manager Catherine McCulloch said it was important to encourage children to get into regular physical activity from a young age.
"The idea is to keep it fun - there are so many things you can do in your own backyard and our Bay of Plenty region has many great resources/open spaces for playing in."
The Active Families programme offers children and families education and support around increasing physical activity and healthy eating.
"The adviser works closely with the families to ensure they can access regular physical activity options that are of interest to them," McCulloch said.
"They support them to ensure food options are healthy; and they encourage the right food habits are established such as eating breakfast regularly, easy snack ideas and appropriate portion sizes."
An adviser also educates the family on label reading so they can make informed choices at the supermarket.
"Short-term goals are made regarding physical activity and nutrition, and reviewed regularly so the family can see how they are progressing."
Siblings Layla, 10, and Hineata Palmer, 9, were involved in the Active Families programme in 2016.
At the time, the girls attended weekly sessions to learn about health and nutrition and were encouraged to take part in events and activities including the Weet-Bix Tryathlon.
"They ended up doing three triathlons," stepmother Moana Ngatai said.
Her daughter, Kahurangi Ngatai, 12, also took part as support.
"They were part of many martial arts programmes too," she said. "They loved it."
Miss Ngatai said the girls had lost weight during the programme. "I think at one point it was about 6kg."
MAKE A CHANGE:
- Enjoy 5 or more vegetables and fruits every day
- Choose fresh vegetables and fruits. Have a variety of natural colours on your plate.
- Play actively for more than one hour each day.
- Get outdoors, learn new skills, and visit friends.
- Limit screen time to less than two hours a day.
- Keep bedrooms free of screens and devices such as computers, phones, televisions, gaming stations and tablets.
- Choose water or plain milk, have no sugary drinks
- Buy fewer and fewer sugary drinks each week until you no longer buy any.
- Dr Jim Miller from Toi Te Ora Public Health Service
